Bidens cosmoides 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Asterales Compositae

Scientific Name: Bidens cosmoides (A.Gray) Sherff
Bidens cosmoides A.Gray var. refracta Hochr.
Bidens xdimidiata O.Deg. & Sherff
Campylotheca cosmoides (A.Gray) Hillebr.
Coreopsis cosmoides A.Gray
Taxonomic Source(s): Wagner, W.L., Herbst, D.R. and Lorence, D.H. 2005 onwards. Flora of the Hawaiian Islands website. Available at:
Identification information: Shrubs up to 2 meters in height, ray flowers bright yellow, pendent. Florets orange w/ yellow stamens.Calyx dark purple becoming green at apex, shinny. Petiole dark purple, stems sprawling or vining, leaves dark green.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v) ver 3.1
Year Published: 2016
Date Assessed: 2016-06-15
Assessor(s): Bruegmann, M., Caraway, V.L. & Clark, M.
Reviewer(s): Walsh, S.
Contributor(s): Tangalin, N., Lorence, D.H., Flynn, T. & Nyberg, B.
Bidens cosmoides has been assessed as Endangered. The taxon is endemic to the island of Kauaʻi and has an extent of occurrence of 230 km2. It has experienced severe and ongoing decline in habitat and numbers due to the impacts of alien invasive plants and animals. Its area of occupancy is 80 km2 and declining. Its distribution is limited, occurring in only five subpopulations located in four threat-defined locations.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

Endemic to the Hawaiian island of Kauaʻi, between 350 and 1,200 m elevation.

Countries occurrence:
United States (Hawaiian Is.)
Additional data:
Estimated area of occupancy (AOO) - km2:80Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:230
Continuing decline in extent of occurrence (EOO):Yes
Number of Locations:4
Lower elevation limit (metres):350
Upper elevation limit (metres):1200
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Total number of individuals in the wild is estimated to be approximately 37,000 individuals among five subpopulations. with the largest subpopulation having approximately 30,000 individuals.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:37000Continuing decline of mature individuals:Yes
Extreme fluctuations:UnknownPopulation severely fragmented:No
No. of subpopulations:5Continuing decline in subpopulations:Yes
Extreme fluctuations in subpopulations:UnknownAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:The taxon is a perennial herb found in Hawaiian mesic forests dominated by Metrosideros polymorpha and Acacia koa. Other associated native plant species may include Elaeocarpus bifidus, Alyxia oliviformis, Exocarpus luteolus, Bobea brevipes, Coprosma waimeae, Cyanea leptostegia, Dianella sandwicensis, Dubautia latifolia, D. laevigata, Kadua affinis, Poa sandwicensis, Peperomia membranacea, Kadua cordata, Labordia helleri, Leptecophylla tameiameiae, Lobelia hypoleuca, Pittosporum kauaiensis, Pouteria sandwicensis, Psychotria mariniana, P. greenwelliae, P. grandiflora, Melicope barbigera, M/ ovata, M. anisata, Syzygium sandwicensis, Scaevola procera, and Cheirodendron ssp.
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): Major threats to this taxon include lack of pollinator, invasive alien plants including Hedychium gardnerianum, Rubus argutus, Passiflora tarminiana, Psidium cattleianum, Erigeron karvinkianum, grazing from goats, rat depredation, habitat degradation by feral pigs, and wildfire. Fortini et al. (2013) characterized this taxon as extremely vulnerable to climate change (vulnerability index 0.792).

Conservation Actions [top]

Conservation Actions: Bidens cosmoides is not listed under the U.S. Endangered Species Act, nor by the State of Hawaiʻi.

Citation: Bruegmann, M., Caraway, V.L. & Clark, M. 2016. Bidens cosmoides. The IUCN Red List of Threatened Species 2016: e.T44116A83788584. . Downloaded on 22 November 2017.
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